The ever recurring growth of fouling organisms on underwater structures such as ships, docks, piers, pilings, fishnets, heat exchangers, dams, piping structures, intake screens, cooling towers and the like is a costly and hazardous problem in both marine and freshwater endeavors. The presence of fouling organisms such as barnacles, zebra mussels, algae, diatoms, hydroids, bryozoa, ascidians, tubeworms, Asiatic clams and the like can weigh down aquatic structures, hamper their hydrodynamics, reduce operating efficiency, increase susceptibility to corrosion, cause degradation and structural fractures, block or hamper water flow and water exchange and the like. A common method of controlling the presence or attachment of fouling organisms is to coat or permeate the underwater structure with a composition which comprises a toxic metal-containing compound such as tri-n-butyl tin or cuprous oxide. Although said compositions are somewhat efficacious antifoulants, they degrade slowly in aquatic environments and are, therefore, ecologically harmful.
Arylpyrrole compounds and N-acylated arylpyrrole compounds are known to be effective insecticidal and endectocidal agents useful in crop protection and animal health; said pyrrole compounds are described in U.S. Pat. Nos. 5,310,938 and 5,328,928, respectively.
It is an object of this invention to provide an environmentally and ecologically sound method of combatting or controlling marine and freshwater fouling organisms without the use of toxic metal-containing compounds.
It is another object of this invention to provide an effective method for protecting aquatic structures against fouling by marine or freshwater fouling organisms.
It is a further object of this invention to provide antifoulant compositions which comprise 2-arylpyrrole and acylated 2-arylpyrrole compounds as the active agents.
It is a feature of this invention that the antifouling methods and compositions are free of heavy metal complexes and toxic metal-containing compounds.
These and other features and objects of the invention will become more apparent from the detailed description set forth hereinbelow.